The invention relates to bearing supports in general and to saddle bearing supports for use in multiple piston, axial type pumps and motors in particular.
The use of multiple piston axial type pumps/motors is widely known. The axial pumps are used for pumping liquid at high pressures, the liquid usually being employed to energize hydraulic systems. The pumps include a rotating cylinder barrel or block in which cylinders and cooperating pistons are arranged. The pistons draw the liquid into the pump and then force the liquid back out at high pressures. Axial piston motors are actuated by high pressure liquid to reciprocate the pistons and rotate the cylinder block producing rotary motion at an output shaft.
In many prior art axial type pumps and motors, a casing encloses the operating mechanism. A drive/output shaft extends through the casing and is rotatably supported by a plurality of bearings. A cylinder block is coupled at one end of the shaft and has a plurality of cylinders formed in a circular row concentric with the shaft. Each cylinder is fitted with a piston which is in contact with a non-rotating swash block. The swash block is rockably supported upon stationary spherical bearing surface. The swash block can be inclined from a neutral position with respect to the saddle to impart reciprocating movement to the pistons.
One of the problems that exists with the prior art axial pumps and motors is the bearing support design employed in the area of the swash block and the saddle. The current art uses a concavo-convex liner or thrust bearing which is seated on either the swash block or the saddle and extends across the full surface of the associated element. As the position or angle of the swash block is changed in order to impart a reciprocating motion to the pistons, a thrust load is applied to the bearing. Thus, an edge loading problem exists where the edge of the element not attached to the bearing contacts the bearing surface. This edge loading causes flex and early fatigue of the bearing.
It is an object of the present invention to provide a bearing support that will eliminate edge loading.
It is a further object of the present invention to provide a bearing support system for an axial pump/motor which will increase bearing life and maintain the bearing under a constant load distribution.